On many of the Citation models, flying Single pilot under the exemption, something not really anticipated by the designers...was an extreme aft CG, sometimes out of limits...some charts in the nose (20lbs) can get it back in...but it was anticipated that two 175lb + pilots were up front as minimum required crew, vs one 200 lb guy.....anther ballast type of thing....R22 helo needs balast if the pilot weighs to little, mainly to give the helo more required weight for a good autorotation....